Voltage Drop - is this good?

[manbeer 0]

Tested voltage drop with most accessories off last night. At idle the car rests at 13.9x, With a variety of music and an Iasca test disc, at the loudest volume i can play the factory stereo at while still sounding decent, the lowest i got it to drop was 12.69, it was mostly between 12.7xx and 12.9 on HARD hits. Electrical system is stock, battery, alt, etc, all stock, no cap/ 2nd battery, extra 0wag ground under hood to battery, extra 4awg ground running to rear of the car where it joins the 1/0 that goes into my amp. Amp is an MTX 81000d running @ 2ohms, Rated 1krms @ 12.5 volts, most people get between 12xx and 14xx on their birth sheets at that voltage. I was just surprised that for no real electrical upgrades it wasn't really fluctuating more than 1 volt. Any thoughts?

This is the only other thing, i tapped into my factory preout from the headunit before it reached the factory amp. This is supposedly a low level signal, but i used a line out converter on it. I'm thinking that perhaps it is giving off a pretty weak signal to the amp. haven't had the chance to test it though.

Edited October 2, 2008 by manbeer

[ABXX49 20]

I think you're safe with that. As long as you don't dip below 12 volts you're good. I think I read that 11v can damage an amp? Someone verify that though.

Just out of curiosity what is the max volume you use on your head unit...i.e. 25/50

[manbeer 0]

I think you're safe with that. As long as you don't dip below 12 volts you're good. I think I read that 11v can damage an amp? Someone verify that though.

Just out of curiosity what is the max volume you use on your head unit...i.e. 25/50

Unless a song is unusually quiet or loud, on 90% of music i do 23-24 out of 32. To be honest, i am really surprised that i'm not getting a much worse drop cause when i was reading about this amp everyone was talking about how much of a current hog it was, and it calls for 150 amp fuse, which makes me think that i am not pushing it to full potential

[manbeer 0]

i just tested the voltage from the rca's leading from the LOC with a couple sine wave sweeps and output level maxed and got a max reading of .297 volts. So i guess having my gain on the amp just about all the way up is just about right.

[Adrian_D 520]

Not dropping below 12.6 is pretty good imo.

[jonbearsmt 919]

are you metering up front or at the amp.

[manbeer 0]

are you metering up front or at the amp.

up front, at the battery

[KU40 173]

What size is your alternator? That's the real question that should be asked. If it's 300 amps, then no I wouldn't expect a drop at all. If it's 60 amps, then yeah that's weird at idle.

[manbeer 0]

What size is your alternator? That's the real question that should be asked. If it's 300 amps, then no I wouldn't expect a drop at all. If it's 60 amps, then yeah that's weird at idle.

I believe they are 110 amps

[jonbearsmt 919]

meter in the rear... as your voltage will be lower from the run alone

[manbeer 0]

meter in the rear... as your voltage will be lower from the run alone

ahhh i always metered drop for the car and not for the amp

[jonbearsmt 919]

i hear ya... but to see actual voltage as the amp sees it you dont think you would get a better idea metering from the rear?

[Tirefryr 1,742]

Too low of a voltage causing damage will depend on the power supply. Unregulated will make more power as voltage increases to a point, where as regulated with stay steady with a +/- shift in voltage. There is no general rule of thumb here as every amp and every power supply will differ.

[manbeer 0]

So i just retested it, same track, same settings, this time i remembered to urn off heated seat, and no interior lights as it was light out.

Resting Voltage

14.04 under hood

14.03 @ amplifier

Lowest drop was 12.9x under hood

12.59 @ amplifier

amp is getting a pretty solid connection from what i can tell. this makes me feel a little more confident about running @ 1ohm with a second battery and better cable (currently using raptor 1/0 which seems like 2 gauge, gonna switch to Kolussus 1/0, which i hear is actually 2/0?)